1. Field of the Invention
The present invention relates to a display apparatus equipped with a burn-in correction function, a burn-in correction system and a burn-in correction method.
2. Related Art
The phenomenon called as burn-in sometimes occurs in a display apparatus equipped with a display panel such as a liquid crystal display (LCD) and a plasma display panel (PDP). The burn-in is the phenomenon in which the trace of a pattern remains on a display screen when the same image has been displayed over a long time, or when the cumulative display time of the same image becomes a long time. If the burn-in occurs, the light emission state of the burn-in place has changed to make it impossible to perform an adequate display. Accordingly, various techniques have been conventionally proposed for settling the burn-in phenomenon.
For example, Patent Document 1 discloses a projector which is equipped with a color unevenness correction circuit and can correct the color unevenness on a projection screen by measuring the luminance of each block of a projected image based on an image signal of a fixed luminance level, which is projected on the screen with a luminance meter or a video camera, by acquiring a parameter for color unevenness correction based on a difference between the measured value and a reference value to set the acquired difference in a register of the color unevenness correction circuit, and by performing the color unevenness correction of the image signal based on the parameter in the register with the color unevenness correction circuit.
Moreover, for example, Patent Document 2 discloses a projection system capable of generating a proper image in conformity to the situation of a projection plane by acquiring an image by the camera unit's imaging of a pattern which is projected by a projector unit and the luminance of which stepwise changes at regular intervals, by the camera control unit's setting of correction values for gradation property correction so that the stepwise variation quantities of the brightness of the area of the acquired image in which the pattern is projected may be arranged at regular intervals, by the γ correction circuit's correction of the gradation property of a photographed image acquired by the camera unit based on the correction value set by the camera control unit after the camera control unit's setting of the correction values for the gradation property correction, and by the device drive control function's correction of the gradation property of the projected image to be projected on the projection plane from the projector unit.
Furthermore, for example, Patent Document 3 discloses a convergence adjustment system performing the adjustment of the distortion of an image by the digital camera's imaging of the whole image projected by a liquid crystal projector to read the image property of the imaged image by means of a program, and by capturing the misalignment in the horizontal direction and the vertical direction of each color signal, the misalignment of the angle thereof, the misalignment in the depth direction thereof, and the misalignment caused by low angle photographing.
[Patent Document 1] JP-A 2006-003607
[Patent Document 2] JP-A 2004-109246
[Patent Document 3] JP-A 2003-264847
Because burn-in is a deterioration phenomenon occurring by the pixel constituting a screen, it is necessary to perform the detection and the correction of a burn-in place by the pixel in order to perform an accurate correction. However, according to the techniques disclosed in Patent Document 1 and Patent Document 2, it is possible to correct color deterioration and the like, but, because both of the techniques correct the parts where color unevenness has occurred by imaging the whole screen with a video camera or the like, both the techniques have the problem of the impossibility of performing accurate detection of a place where color light emission is deteriorated to perform adequate correction. Moreover, the technique disclosed in Patent Document 3 can capture the misalignment quantities, but cannot perform the detection and the correction of burn-in by the pixel, and consequently cannot accurately correct color deterioration owing to the burn-in.